Learners will explore spacecraft radio communications concepts, including the speed of light and the time-delay for signals sent to and from spacecraft. Learners measure the time it takes for a radio signal to travel to a spacecraft using the speed...(View More) of light, demonstrate the delay in radio communication signals to and from a spacecraft, and devise unique solutions to the radio-signal-delay problem. In an extension, learners are asked to calculate the distance the spacecraft traveled. All NASA spacecraft missions have a telecommunications system and use radio waves to transmit signals. The context for this activity is sending a command to the New Horizons spacecraft telling it to take a picture of Pluto. Includes teacher background, adaptations, and student data sheets.(View Less)